Constructing a perfect, efficient heterojunction catalyst with HNO3 protonated C3N4 and GO-derived GOQDs via electrostatic self-assembly

Abstract

To improve the photocatalytic performance, carbon nitride (C3N4) heterojunctions with carbon nanomaterials are being developed. Here, the electrostatic self-assembly method was used to create the GOQDs (graphene oxide quantum dots)/Hp-C3N4 (HNO3 protonated carbon nitride) heterojunctions. Poor dispersion and weak interface bonding were addressed by using GOQDs, a derivative of graphene oxide (GO). The specific surface area of the GOQDs/Hp-C3N4 heterojunction increased from 7.445 m2/g to 33.634 m2/g, and the valence band potential increased from 2.016 eV to 2.367 eV. The GOQDs/Hp-C3N4 could generate higher levels of •OH and superoxide radicals (•O2-). The degradation efficiency of the heterojunction for pollutants (MO) under visible light was increased by 343, 9, and 4 times in comparison to C3N4, Hp-C3N4, and GO/Hp- C3N4, respectively. Our results showed that GOQDs derived from GO with smaller sizes and higher abundances of oxygen-containing functional groups make better co-catalysts for constructing heterojunctions with C3N4 to boost photocatalytic performance.